The invention relates to a method for providing driver information in a motor vehicle, in which method a recording device of the motor vehicle captures an image flow containing images of at least one part of the environment, i.e., the surroundings of the motor vehicle, a display unit in the interior of the motor vehicle reproduces at least one image section of the image flow, and a display control unit of the motor vehicle automatically modifies the environmental section shown to the driver by reproducing the image section using the display unit.
Such methods have been disclosed in DE 100 36 875 A1, EP 1 211 132 A2, and DE 20 2006 015 992 U1. For example, a monitoring of the rearward vehicle environment can be improved by the devices described in these documents to the effect that a camera for rear-area monitoring is disposed directly on the rear end of the vehicle as a result of which the camera is positioned to more suitably view the close-in rearward vehicle environment than is a rear-view mirror disposed in front of the driver's seat by virtue of its functional principle. However, the documents specified above do not deal with measures for assisting the user in interpreting the environmental section represented.
It is an object of the present invention to provide a method by which a user is better assisted in interpreting the environmental section represented.
This and other objects are achieved by a method according to the invention, in which a recording device of the motor vehicle captures an image flow (e.g., MPEG video stream or a sequence of non-interlaced images) containing images of at least one part of the environment of the motor vehicle. A display unit in the interior of the motor vehicle reproduces at least one image section of this image flow. For example, the recording device can deliver an image flow comprising 1920×1080 pixels and the display unit reproduces a rectangular section of 240×180 pixels from this image flow. The environmental section represented by the display unit such as a TFT display is thus determined firstly by determining the image section of the image flow and secondly by determining that part of the environment that is represented in the image flow. The image flow itself can be limited to a relatively narrow portion of the environment such as the rear area of the vehicle. In the opposite extreme case, the image flow can also be formed into a panorama view of the vehicle environment. Particularly, one or more cameras can be used as recording device, and so can other imaging devices. In the case of several cameras used jointly simultaneously or alternately as recording devices, the individual cameras need not record those parts of the environment that happen to overlap or adjoin each other.
In the method according to the invention, a display control unit of the motor vehicle additionally automatically modifies the environmental section shown to the driver by reproducing the image section using the display unit; for example, the display control unit adapts the environmental section to changed ambient conditions or a change in the position of the motor vehicle. In order to adapt the environmental section, the recorded part of the environment can be adapted according to the above remarks by panning a camera used as the recording device or by switching over to another camera, and/or the reproduced image section is adapted. In the above example of a rectangular image section, in particular, its position in the image flow originally delivered by the recording means can be modified. The term “determination or adaptation of the environmental section” is naturally not meant to connote an active intervention in the environment, but instead one of the measures addressed above relating to recording and/or reproduction. Particularly a purely virtual camera pan or a purely virtual camera switching can be carried out from the view of a user observing the display unit when the selected image section is shifted in the image or image flow recorded at a wide angle. Optionally, when the selected image section in the image or image flow recorded at a wide angle is selected to be larger or smaller, a virtual or digital zoom further takes place; that is to say, the aperture angle required by a camera in order to record the image section represented is changed.
The fact that the change in the environmental section is effected automatically relieves the driver of performing this change manually. However, it can also prove too taxing for him. As described above, when the display control unit adapts the represented environmental section such that a hazard source in the vehicle environment is displayed to the driver, a switchover or pan of the environmental section represented takes place without any effort on the driver's part. Particularly when this switchover or pan takes place very rapidly and/or when the driver cannot fully concentrate on observing the display unit due to the actual driving task, it may happen that the driver loses his orientation relative to the represented environmental section in the absence of further assistance. In order to prevent the same, according to the invention, the driver is provided with at least one lot of additional optical information from which he can identify the environmental section that is currently displayed to him. In other words, during the reproduction of the image section, in addition to the representation of the environmental section, at least one lot of optical information relating to the position of the environmental section relative to the motor vehicle is output to the driver. The observer is thus provided with the possibility of orienting and classifying the displayed environmental section in the overall environment.
The term “in addition to” must be understood to mean that the reproduction of the image section comprises more information than a mere representation of the environmental section; that is to say, more information than the pure image content of the image section determined by the display control unit. This information can be “packaged” in a special form of reproduction of the image section. The invention can thus be implemented by a reproduction of the image section alone if the image section is reproduced such that information, which extends beyond the pure image content and relates to the position of the environmental section relative to the motor vehicle, is delivered. Alternately or additionally, an additional visual display can be output in order to deliver such information.
The term “position of the environmental section relative to the motor vehicle” used above is meant to be understood at least as a horizontal direction, and additionally a vertical direction, if appropriate. Since the movement of the motor vehicle and other road users is substantially played back in a plane, mainly the horizontal direction of the environmental section relative to a reference axis of the motor vehicle, such as the vehicle longitudinal axis, is decisive for a successful interpretation of the environmental situation by the driver. However, in special situations, the vertical direction can also be of importance, for example, when the screen area is automatically oriented, depending on the situation, to a towering landmark in the vehicle environment.
According to a preferred embodiment of the present invention, the image section itself is reproduced—and thus, the environmental section is actually represented—as a function of the position of the environmental section relative to the motor vehicle. The idea of the invention is thus implemented particularly elegantly.
In such an implementation of the invention, the observer can also acquire information relating to the aforementioned position, in most cases based on a mere observation of the image section that is required anyway for detecting its contents. The driver then need not interpret any additional representation elements. There is also no requirement of any technical effort for providing such representation elements. The position-information delivered merely with the help of the reproduction of the image section itself can additionally be interpreted by most observers intuitively.
According to a preferred embodiment of the present invention, the image section is reproduced as a function of the position of the environmental section relative to the motor vehicle by arranging the image section, corresponding to this position, within a larger display surface of the display unit. The majority of observers can intuitively correlate between the position and the arrangement.
Particularly the display unit can be integrated into the reflecting surface of a rear-view mirror of the motor vehicle. The display unit itself can also be formed as the reflecting surface of the rear-view mirror, and the display surface that is not currently used for representing the environmental section can be transferred into a reflective state. In such an embodiment of the invention, the observer can easily recognize, based on the arrangement of the image section within the reflecting surface, the part of the environment currently displayed to him. The remaining parts of the mirror continue to be usable by the driver in the conventional sense.
According to another alternately or additionally applicable preferred embodiment of the present invention, the reproduction of the image section as a function of the position of the environmental section relative to the motor vehicle is implemented by reproducing the image section in a distorted manner corresponding to the position.
The distortion can be achieved by subjecting the image section to a geometric transformation that gives the observer the impression of a corresponding perspective. The distortion can alternately or additionally also be achieved by means of a curvature or a perspectively generated virtual orientation of the image section.
The majority of drivers can also intuitively correlate between such a distortion and the position to be represented. The combined use of distorting the image section, corresponding to the position, and arranging the image section, corresponding to the position, within a larger display surface is particularly effective. Easily interpretable representation results can also be achieved without any variation in the arrangement. It is also sufficient to have a smaller display surface without any variation in arrangement.
According to another alternately or additionally applicable preferred embodiment of the present invention, the reproduction of the image section as a function of the position of the environmental section relative to the motor vehicle is implemented in that the image section is arranged, corresponding to said position, in a defined plane of a three-dimensional representation.
Also a representation of the environmental section as a function of a zoom factor or aperture angle used for determining the environmental section or resulting from the determination of the environmental section can be advantageous. As a preferred variant of a reproduction of the image section as a function of this zoom factor or aperture angle, it is suggested that the image section be arranged, corresponding to said zoom factor or aperture angle, in a defined plane of a three-dimensional representation.
Alternately or additionally to the aforementioned embodiments, the representation of the environmental section can also be accompanied by a symbolic representation of the position of the environmental section relative to the motor vehicle.
This can also enable the observer an improved orientation and classification of the represented image section in the overall environment.
The same display unit that displays the image section itself preferably displays the accompanying symbolic representation. However, any other display device can also be selected or provided in the driver's field of view for the purpose of representation.
Alternately or additionally, information relating to a zoom factor or aperture angle used for determining the environmental section or resulting from the determination of the environmental section can be delivered to the driver by way of an accompanying symbolic representation.
The above remarks deal predominantly with the representation of an environmental section determined automatically by the display control unit.
Additional preferred embodiments and advantageous improvements of the invention described below will focus on the determination of the represented environmental section by the display control unit, which determination precedes the representation by virtue of its functional principle.
A preferred embodiment of the present invention pursues the goal of showing the driver, by means of the environmental section represented, exactly those image contents that are most likely to be of interest or use to him. This embodiment is based on the finding that particularly those road areas are to be considered as being of particular interest and/or use to the driver that have been traveled on by the motor vehicle itself (shortly) before. Since the trajectories of motor vehicles moving in traffic are typically strongly influenced by the routing and configuration of streets and roads, and lanes, there exists a particularly high probability, exactly at those locations where the subject vehicle has slowed down shortly before, of catching sight of a subsequent motor vehicle. In the use of a conventional rear-view mirror oriented such that it provides a view of the rearward vehicle environment substantially along the vehicle longitudinal axis, the aforementioned road area is typically not contained in the mirror image, particularly after strong changes of direction of the motor vehicle. Also known camera-based rearview systems do not offer any solution for the targeted monitoring of this road area in such situations.
For solving this problem, a device is provided for determining at least one previous position of the motor vehicle, in which device the environmental section represented by the display unit can be adapted automatically as a function of the previous position of the motor vehicle. The environmental section can thus be adapted such that particularly, and optionally even exclusively, those road areas are contained in the environmental section that have been traveled on previously by the motor vehicle. As remarked above, an adaptation of the environmental section involves adapting particularly the recorded part of the environment by panning a camera used as the recording devices or switching over to another camera, and/or the reproduced image section can be adapted.
The previous position to be determined and to be taken into account in the adaptation can be defined, for example, as the position at a defined point in time that dates back from the current point in time by a predetermined period of time or as the position trailing in relation to the current vehicle position by a longitudinally determined route. The at least one previous position can be determined e.g., relative to the current position of the motor vehicle and/or in absolute terms, e.g., in GPS coordinates.
The term “previous position of the motor vehicle” used here can be interpreted variably depending on the exact variant of implementing the invention. It can be understood to mean the center of gravity and/or the geometric center of the motor vehicle located above the roadway plane at the respective previous point in time. The term can also be understood to mean a projection of the center of gravity and/or geometric center above the roadway plane. Likewise, the term “previous position of the motor vehicle” used here can be understood, notwithstanding the actual wording “position,” as “extended volume” or “extended surface.” Within the meaning of a volume, the term can be understood to mean the volume filled out by the vehicle at the respective previous point in time, optionally approximated by a simplistic geometric model such as a parallelepiped. Within the meaning of a surface, the term can be understood to mean the area taken up by the vehicle on the roadway at the respective previous point in time, optionally approximated by a simplistic geometric model such as a rectangle. Such a surface can again be defined, depending on the embodiment, as one “lying” on the roadway or “floating” at a defined height above the roadway, for example, at the height of the center of gravity and/or geometric center.
When mention is made in connection with this embodiment of the invention, of a previous position of the vehicle being contained in an environmental section and the previous position being defined as the point or surface within the roadway plane, it means that the environmental section is determined such that the corresponding part of the roadway surface is contained in the environmental section unless it is hidden by another object. When mention is made in connection with this embodiment of the invention, of a previous position of the vehicle being contained in an environmental section and the previous position being defined as the point, surface or volume above the roadway plane, it means that the environmental section is determined such that a hypothetical object disposed at this point, in this surface or in this volume would be contained in the environmental section unless it were hidden by another object.
An embodiment of this invention that can be implemented with particular ease provides for determining the previous position only with respect to its direction relative to the current vehicle orientation. A considerable improvement over prior-art systems can be achieved by merely appropriately selecting the environmental section such that the latter is determined solely by the orientation of the effective viewing angle in this direction.
Due to the small vertical extension of the traffic-related parts of the vehicle environment—considering that the vehicle and all other road users move on the road surface—the previous position can be determined particularly effectively merely with respect to its horizontal direction relative to the current vehicle orientation.
Preferably, in addition to the direction of a previous position relative to the current vehicle orientation, at least the distance of the previous position relative to the current vehicle position is also determined and taken into account. This distance can be used accordingly for determining an effective zoom factor of the image section when determining the environmental section.
For the sake of simplicity, it is assumed below without loss of generality that due to the aforementioned small vertical extension of the traffic-related parts of the vehicle environment, no vertical determination of the image section is necessary over and above that vertical change of the image section that involves a zoom-in or zoom-out for changing the horizontal image section. Naturally, the idea of the invention can be implemented similarly taking into account the necessity of a vertical determination of the image section.
According to a particularly preferred embodiment of the present invention, included is a device for determining a plurality of previous positions of the motor vehicle; at least one preferred display section in the environment of the motor vehicle being determinable as a function of this plurality of previous positions and the environmental section being adaptable such that this display section is displayed. As a result of taking into account a plurality of previous positions of the motor vehicle, the environmental section can be adapted, to particular advantage.
As discussed above, each individual previous position can be formed as a point, surface or volume. Thus, the plurality of previous positions is basically formed as a point set, a line, a set of single surfaces, a tubular surface, a set of single volumes or a tubular volume. Without loss of generality, the previous positions discussed below will be regarded as being point-shaped. The plurality of previous positions is thus formed as a point set or a line.
The plurality of previous positions can be formed or can be present as a trajectory of the motor vehicle, for example. Such a trajectory can describe the previous path of motion of the motor vehicle continuously, quasi-continuously or as a value set. For restricting such a value set or value sequence, the most recent portion of the previous path can be recorded in a circular buffer or any other memory device in which older values are rewritten.
The display section can be understood to mean a required environmental section. If permitted by the technical parameters of the device, the environmental section can be adapted such that it exactly matches the display section. The environmental section is then determined or adjusted directly as a function of the plurality of previous positions. If appropriate, specific allowances can be made in this regard and the environmental section is adapted only essentially to match the display section.
In the simplest case, the display section can be determined as a direction relative to the current vehicle orientation. However, the direction can also be supplemented by a zoom factor, for example.
The previous positions can be determined and/or processed as absolute positions. For example, positional specifications of a satellite-based system for determining positions (e.g., GPS) can be used in this connection. In such a case, the preferred display section is also determined, at least initially, in absolute terms. In the case of a known current vehicle position and optionally vehicle orientation, the preferred display section determined in absolute terms can be converted into a preferred display section that has been determined relative to the current vehicle position and optionally vehicle orientation.
Alternately, positions and optionally orientations exclusively relative to the current motor vehicle position or vehicle orientation can be determined and/or processed as previous positions. For determining such relative values, particularly steering angle signals and/or speed signals and/or acceleration values measured using a gyroscope, for example, can be used.
The display section is preferably determined such that defined predetermined criteria, which must be met in connection with the previous positions, are fulfilled to the best possible extent.
For example, one criterion may be defined as the requirement for all positions occupied by the motor vehicle on a defined previous driven distance of predetermined length (e.g., one meter multiplied by the current speed measured in kilometers per hour), to be contained in the display section or in the environmental section. An additional criterion can be the requirement to select the display section or environmental section to be as small as possible in order to provide a good detail representation. If the display section or environmental section can be adjusted with the aid of the two parameters of direction and zoom factor, there usually exists an optimum value of these parameters, for which the two criteria, as a whole, are met to the best possible extent.
Alternately to such a criterion, a center of gravity of the plurality of previous positions can be determined, for example. The display section or environmental section can then be determined such that this center of gravity is located at the center of the display section or environmental section. Depending on the distance of the center of gravity from the motor vehicle, a zoom factor of the display section or the environmental section can be determined.
According to another particularly preferred embodiment of the invention, the display section or environmental section is determined such that it is delayed in time relative to a fictitious display section or environmental section that is constant relative to the vehicle. As a result of such a time delay that can be in the order of magnitude of a second, for example, in the case of a strong change of direction of the motor vehicle, the display section and thus also the represented environmental section are initially retained in the manner prevailing before the change of direction. Consequently, a subsequent vehicle does not immediately disappear from the represented environmental section in the case of a change of direction of the subject motor vehicle, but instead, it is possible to observe, for example, whether this subsequent vehicle is signaling by way of the blinkers or whether it is delivering other optical signals (e.g., headlight flashers) in order to warn the subject motor vehicle of the invention of the presence of a hazard at a turn. Such a time delay can also be advantageous in connection with determining the display section or environmental section according to other criteria.
According to another particularly preferred embodiment of the invention, the display section or environmental section is determined such that its time course is low-pass filtered in relation to a fictitious display section that is constant relative to the vehicle. Thus, a high-frequency part of the vehicle movement is filtered out or compensated. In the case of a double bend, on which the motor vehicle has traveled fast, or a rapidly executed lane change by the motor vehicle, the low-pass filtering can prevent the driver from losing a view of the rearward environmental area of the motor vehicle. Such a low-pass filtering can also be advantageous in connection with determining the display section or environmental section according to other criteria.
In many feasible algorithms for determining the display section or environmental section, a low-pass filtering and also a time delay are brought about, by virtue of their functional principle, by taking into account the previous positions of a previous time interval of defined length.
This effect can be reduced particularly by including the previous positions, depending on the extent to which they date back in time and/or their distance from the current vehicle position, with variable weighting, in the determination of the preferred display section or environmental section, and by weighting recent values more heavily. Other filter effects are possible if the previous positions, depending on the extent to which they date back in time and/or their distance from the current vehicle position, are included, with variable weighting, in the determination of the preferred display section or environmental section.
The preferred display section or environmental section is preferably determined based on a quality criterion. In doing so, it is possible, as mentioned above, to evaluate whether and/or where the previous positions of the motor vehicle are contained in the display section or environmental section.
In the simplest case, it is only evaluated whether defined previous positions of the motor vehicle are contained in the display section or environmental section at all. The display section or environmental section can then be determined clearly in most cases based on the requirement of selecting the smallest possible zoom factor and selecting the viewing direction such that the most extreme previous positions to be represented are located exactly in the border area of the display section or environmental section.
As an alternative or addition to the evaluation as to whether previous positions are contained in the display section or environmental section, it is also possible to carry out an evaluation to identify where the previous positions are contained in the display section or environmental section. If appropriate, one may anticipate the possibility of a previous position to be represented per se not being contained in the display section or environmental section, but other previous positions being represented even better.
If the display section or environmental section, to which a maximum or a satisfactory value of the quality criterion is assigned, can be determined directly, it is preferred to directly determine the display section or the environmental section accordingly. Otherwise, the display section can be determined by means of a search-step procedure or any other optimization procedure, if appropriate.
For the sake of simplicity, without loss of generality, the distinction will no longer be made below between display section and environmental section. However, it will be assumed in the subsequent description that a required environmental section is indeed determined in a defined manner, but the actually effectively adjusted environmental section does not exactly match the required environmental section at all times.
The environmental section is preferably adapted not only as a function of the at least one previous position of the motor vehicle but also as a function of the travel speed of the motor vehicle. Particularly, a wide-angled environmental section at low travel speed, e.g., in the case of parking maneuvers, can ensure an improved view. In contrast, at higher travel speeds, an environmental section that is focused at a narrow angle can be helpful for an improved view of those parts of the environment that are disposed farther off.
It can be advantageous if the environmental section is adapted not only as a function of the at least one previous position of the motor vehicle but also as a function of at least one future position of the motor vehicle.
Particularly, the preferred display section can be determined as a function of a predicted position and optionally a predicted spatial orientation of the motor vehicle. The prediction can precede the predicted future position of the vehicle by a predetermined period of time or a predetermined route of the motor vehicle. For example, the prediction can be made based on the current travel speed and/or the current steering angle. Also longitudinal and transverse acceleration values can be taken into account for improved prediction.
According to a particularly preferred embodiment of the present invention, the motor vehicle comprises a device for determining a plurality of previous steering angle values of the motor vehicle, and the display control unit determines at least one preferred environmental section as a function of the plurality of previous steering angle values. The steering angle values can be used particularly as the essential or the sole basis for determining previous positions of the motor vehicle, with the help of which the environmental section can then be determined. The previous steering angle values allow at least an approximate determination of the previous driving lane of the motor vehicle relative to its current position. The measurement devices and algorithms for implementing the invention can be configured easily with the support of steering angle values and the invention can be implemented effectively.
According to another particularly preferred embodiment of the present invention, the at least one previous position is determined, among other things, with the aid of electronic map data. Particularly, an entire previous trajectory of the motor vehicle or portions of such a trajectory can be determined based on a street course known from such an electronic roadmap. It is also contemplated to make additions or corrections in a trajectory with the help of a street course known from an electronic roadmap, if the trajectory derived otherwise is interrupted due to measurement errors or if it does not seem plausible.
Preferably, the environmental section can be adapted automatically depending on the situation, not only as a function of the at least one previous position of the motor vehicle but also as a function of additional state variables of the vehicle environment.
For example, it is contemplated to adapt the environmental section as a function of known hazard sources or other road users. The previous knowledge about hazard sources required for this purpose can also originate from an electronic roadmap. It can also be obtained wirelessly from a service provider. Information on the presence and, optionally, the exact position and/or additional data of other road users can be provided to the motor vehicle, for example, by means of vehicle-to-vehicle communication and/or vehicle-to-infrastructure communication.
If another road user, particularly another vehicle, is equipped with an RFID chip or other detectable features, this road user can be detected and localized based on a recognition of this chip by the subject motor vehicle or an infrastructure facility. The orientation of the recording device and/or the image section can then be adapted in such a way depending on the situation and a risk potential attributed to the other road user that the environmental section displayed includes the other road user.
In addition to other road users, other objects and states of the vehicle environment can also be detected with the aid of the RFID chip as the subject vehicle drives past the same. For example, the RFID-based detection and optionally localization of traffic signs, intersections, side-roads, junctions, traffic lights and parking facilities is conceivable. The environmental section can also be adapted depending on the situation as a function of such objects and the arrangement thereof relative to the motor vehicle.
The RFID detection can also relate to objects that do not directly concern the driving process, e.g., mailboxes, restaurants, cigarette vending machines, etc. The environmental section can also be adapted in such a way depending on the situation that such objects are displayed to the driver. The driver can thus be provided, for example, with an image representation of a free parking space in the vehicle environment.
In addition to the RFID-induced adaptation of the environmental section represented, the display unit provided as suggested by the invention can display at least one lot of information, which is read out from the respective RFID chip and which relates to the object equipped with the RFID chip. Instead of the display of information with the aid of the display unit, naturally any other information-exchange unit can also display the information. The image section can be adapted in such a way, as mentioned above, that a free parking space is displayed to the driver in the environmental section represented. Moreover, the amount of the parking fee incurred for using the parking space can also be read out as additional information from the RFID chip and displayed to the driver by fading in the information into the image of the environmental section or providing the information at any other location in the vehicle interior.
The situation-based determination addressed in the preceding section can rival the determination of the environmental section addressed above, which provides for an orientation toward previous vehicle positions. Therefore, the weighting of various influencing variables can preferably be adapted by a vehicle occupant's operations when determining the environmental section. Particularly, it can be advantageous to define a threshold that a mathematical measure of the relevance of a traffic situation must exceed so that the environmental section is determined as a function of this traffic situation. If the threshold is not exceeded, the environmental section is adapted, as before, as a function of at least one previous position of the motor vehicle.
According to another advantageous improvement of the present invention, a change in the environmental section, which change is caused by a pitching or rolling movement of the motor vehicle, can be compensated by a reverse adaptation of the image section. For example, a rear-space view displayed is thus not falsified by a pitching movement of the vehicle when the brakes are pressed hard. A measurement or estimation of the disturbance variables to be compensated is helpful for the purpose of implementation.
Also the macroscopic course of the street traveled on by the motor vehicle can be compensated. In order for another vehicle traveling behind the subject motor vehicle to be contained in the environmental section, it is not sufficient to compensate the pitching and/or rolling movements of the motor vehicle in relation to a street surface approximated as a single flat surface. If the motor vehicle is initially traveling on a substantially flat street and then suddenly inclines strongly rearward for a brief period of time while ascending a locally narrow slope, then it is necessary to first compensate the inclination of the motor vehicle relative to the local street surface and secondly the inclination and height of this local street surface in relation to the plane in which the subsequent vehicle is located. Such data can be derived from electronic map data of a navigation system. Alternatively, if the motor vehicle has detection devices suited for this purpose, the absolute height and the absolute pitch angle of the motor vehicle in space can be determined. If additionally the previous position, to which the environmental section is to be adapted, is known in absolute terms in space, then the recording means and/or the image section can be adapted accordingly.
According to another advantageous improvement of the present invention, a change of the environmental section caused by a vibration of the motor vehicle can be compensated by a reverse adaptation of the image section. The image flow of a rear-area view can thus be stabilized electronically, for example, during travel over a cobbled pavement that causes the entire vehicle and thus also the recording device to vibrate. A measurement or estimation of the disturbance variables to be compensated is helpful for the purpose of implementation.
According to another preferred advantageous improvement of the present invention, the image section is compressed, at least intermittently, in at least one border area relative to a central image area in order to bring about a representation of the environmental section corresponding to a representation using a non-spherical mirror. The entire viewing angle can thus be enlarged without reducing or distorting the image in the central image area.
According to another advantageous improvement of the present invention, the device includes a device for determining the user's eye position and/or viewing direction, and the environmental section can be adapted as a function of this eye position and/or viewing direction. The driver is thus provided with the possibility of interacting with the device in the same manner, as he is accustomed to in the case of a conventional mirror. For example, a transition can be made to a wide-angled representation when the driver's gaze approaches the display unit. If appropriate, this effect can also be intensified more than proportionally. The driver is thus provided with the improved or added possibility as compared to the use of a conventional mirror, of interacting with the device. Nevertheless, due to the similarity in possibilities for interaction, this function of the device is intuitive for most drivers and can be used specifically without necessitating any noteworthy adjustment period on the driver's part. However, it can be advantageous to increase the zoom factor when the driver's gaze approaches the display unit. This can also meet the expectations of many users and is thus intuitive for such users and can be used specifically without necessitating any noteworthy adjustment period on the driver's part. Instead of the eye position, the head position of the user, particularly the driver, can also be detected if it is easier to do so in terms of technology.
According to another advantageous improvement of the present invention, the device includes a device for illuminating the vehicle environment, and the illumination of the vehicle environment is controlled as a function of the environmental section currently displayed. Thus, directed light sources and their orientation toward the environmental section can be used to specifically illuminate that part of the vehicle environment at all times that is actually restored in the display to the driver. Naturally, this goal can also be achieved if the illumination of the vehicle environment is controlled in such a way as a function of the at least one previous position of the motor vehicle that the environmental section currently displayed is illuminated in a defined manner, for example, as brightly as possible.
The headlights (particularly low-beam lights, high-beam lights and/or back-up lights) that are provided anyway in the motor vehicle can be used for the illumination if their light can be oriented and/or redistributed. Particularly in this case and in other cases of the use of visible light, the change of the illumination of the vehicle environment can contribute toward enabling the environmental section to be better represented as suggested by the invention and enabling the driver and other road users to have a better view of said environmental section.
The illumination of the vehicle environment can also be carried out in infrared spectrum if the recording means used according to the invention operate in the infrared spectrum. In this case, the changed illumination of the environment does not irritate other road users.
The idea of the invention can basically be applied to all devices used for monitoring the environment of a motor vehicle that provide the driver with an image representation of a section of the vehicle environment and are technically suitable for implementing the features of the invention. Devices that can provide the driver with an image representation of the section of the vehicle environment may be subsumed under the term “imaging devices.” Imaging devices in this sense include both devices based on camera images (also infrared) and those that are based on synthetic images (optionally also with a symbolically represented vehicle environment), and images generated, for example, by scanning the environment with the aid of a radar device, a LIDAR device or similar detecting means. An object in the environment of a motor vehicle can also be recognized if it has an RFID chip or a similar detectable feature. Such an object detected with the help of an RFID chip could be plotted, for example, in an environmental image generated synthetically using a radar device. The term “recording of an image flow by recording device” used above also includes such cases of real-time image generation based on a detection of the environment. An imaging device in the above sense can also consist of several cameras and/or other sensors whose images are joined together to form a single image.
The display control unit can be formed, for example, as a motor-vehicle control unit. When designed appropriately, it can also perform, apart from the tasks cited above, additional tasks that may and/or may not be associated with the present invention.
Preferred exemplary embodiments of the invention will be described below with reference to the accompanying drawings. Additional details, preferred embodiments and improvements of the invention will become apparent therefrom. The exemplary embodiments, design forms and improvements described are applicable and advantageous both individually and in any combination with each other, unless otherwise specified and/or excluded technically. Some exemplary embodiments, particularly those relating to the determination of the environmental section, are also applicable independently of the invention.